Charles II, King of Bohemia, King of Hungary, Margrave of Brandenburg, Duke of Luxembourg and Holy Roman Emperor, attempted to steer the vast collection of Luxembourg territories in a slightly less controlling manner than his father had. However he would largely end up back at square one thanks to a combustible religious situation in Bohemia and constant war in Germany.

The eldest son of Wenceslaus I and Adelaide of Hungary, Charles was brought up as an integral member of Wenceslaus's itinerant court though had a special affinity for Hungary. He often acted as his father's regent there whilst he was in other parts of the Luxembourg realm. There he would lead expeditions against Byzantium and also across the Adriatic where Hungarian troops were propping up the beleaguered Kingdom of Naples. He would also oversee a massive transfer of royal property to the Hungarian barons, a necessary step to pay for Wenceslaus's wars but one which would weaken the crown.

On his father's death in late 1400 Charles quickly toured the Luxembourg lands to receive homage from the nobility and was invested with the various crowns. Now free to make his mark he attempted to restore the crown's powers in Hungary, a move which was violently resisted and he would be forced to campaign against his own restive lords, eventually defeating his chief enemy, Ladislaus Horvat, who was killed, in a pitched battle at Székesfehérvár in May 1402. While the military aspect was now over Charles had to tactfully climb-down from his wish to recentralise the state; the Hungarian lords remained just too opposed to make it work. Instead it would take most the rest of his reign and slow incremental steps before he could confidently say he held the balance of power in the kingdom. Hungary was not the only area in which his power was less than total however.

Though he had been granted the Italian crown early on the wider Imperial crown eluded him; the German Electors were far too divided to hand him it without a fight. While Hungary still simmered with tensions following the death of Ladislaus Horvat Charles's first moves toward securing the Imperial throne were foiled by Rupert of Wittelsbach renewing his vendetta against the Luxembourg family, securing Swabian, Prussian and even Papal backing. Anglia and its Flemish Electorate had switched to the Luxembourg side however and Milan would successfully stop his march on Rome in 1402. Rupert therefore failed in his bid to have himself crowned and the two sides embarked on a half-heartedly waged civil war to force the other to renounce the throne. Rupert was hamstrung by the poor state of his finances whereas Charles, concentrating his time and ability on Hungary and Italia, seemed almost idle in not forcing his hand in Germany. It would only be on Rupert's death in early 1408 that Charles could confidently secure the backing of most of the electors and would be crowned in Aachen in June 1408.

Charles II's second wife, Valentina of Milan

With this once again a Luxembourg king ruled over half of Europe (albeit tenuously in parts). He had however taken note of his father's incessant tinkering with all parts of his realm; a never-ending task which had left him exhausted and defeated. Charles sought to adopt a less personal approach and divided the rule of the lands up between his relations. In the Reformatio Carolus a whole raft of duchies were created while Charles retained the crowns, and ultimate sovereignty. His brothers Jobst and Wenceslaus were given Neumark and Moravia respectively. His sons Sigismund and Matthew, Slovakia and Croatia. His daughter Catherine was given Luxembourg. In the main these were meant to strengthen borderlands, especially the Polish border, however as the lands could, at any point, be re-appropriated by the king (and they were meant to be reaffirmed upon each party's succession) there was little incentive to improve the lands for the greater good, instead it merely lined the pockets of the sub-rulers and fuelled competition between the relatives.

In the end however all of the duchies would end up reverting to Charles (or his sons) as the other branches died without heirs. He would have to fight for possession of Luxembourg after Catherine's death in 1420 when her widower Philip de Saint Pol claimed it as his dowry. In the end his son Matthew would again have a monolithic empire too big and contradictory to steer effectively.

In Bohemia Charles would be much occupied with the activities of the reformist cleric, Jan Hus. Hus loudly preached the reform of various church practices taking the Anglian theologian John Wycliffe's work as a starting point, even going so far as to criticise the papacy. By 1410 the church's administration was riled enough to denounce him but attempts by Prague's archbishop to reign in Hus only led to riots on the streets. Increasingly, to keep order if anything, Charles and his Bohemian ministers took Hus's side. This only empowered Hus more however and, condemning the sale of indulgences (which effectively bankrolled the papacy and its wars) led to Prague being placed under an interdict. The more moderate voices of Prague University were crowded out and many of the German students and doctors left the kingdom for growing towns such as Leipzig. In 1412 papal bulls declaiming his ideas were publicly burnt and all the while his ideas and writings were spreading into Poland, Hungary and Germany.

The execution of Jan Hus, Augsburg 1417

Despite having fought hard for eight years to recover the Imperial crown Charles was soon deeply embarrassed by the title. Not only had he failed to comprehensively defeat the Wittelsbachs and Hapsburgs but faced an uphill struggle to contain Italian passions. One policy he hoped would secure his legacy would ultimately come back to haunt him. His father had successfully healed the Papal Schism of the 14th century but there were many aspects still lingering and causing friction, such as donations, or relics and blessings the differing anti-popes had made. Charles hoped that a successful reform of the religious sphere would give him enough heft to attempt a political reform of the Empire. A Council at Augsburg in 1416 took two years to collect reports from all over Europe, and Leifia, of various rulings the competing popes had made and to reconcile the parties over Hus's teachings. Deliberations took almost two years but did much to clear up the embarrassing discrepancies. Charles oversaw much of the procedings however was away in 1417 when the council made its most far-reaching verdict; condemning Wycliffe's writings as heresy and condemning Jan Hus to be burnt at the stake as a heretic.

The Bohemian followers of Hus reacted with swift anger, raising arms against their king. How complicit Charles was in the execution, considering he had previously given Hus promises of protection, is debatable but he in turn announced a war against the heretics, saying he would drown all Hussites, a move which only served to bolster the Hussite side. With no help coming from the German princes, continuing trouble on the Byzantine border, and Poland and Denmark eagerly helping to undermine its neighbour, Charles lost all control over the situation. The well-armed and well-led Hussite armies defeated not only Charles' army but six successive crusades against them, as well as raiding into eastern Germany and Hungary. It was only when they themselves fell into factional disputes that Charles and his successors could gain the upper hand.

In 1413 relations with France, never particularly good, took a nose-dive. France had used the civil war in Germany to build a bloc out of the Francophone states on the Empire's western borders and in that year declared a regency over Bar whose Duke had been declared insane. The German states typically did not feel the need to react or assist Charles and he was forced to rely on Arles, Auvergne and Anglia to restrain French ambition. The French state had rebounded strongly from its nadir in the mid-14th century and confidently and ruthlessly saw off most attempts to defeat it. The Bar War would drag on until 1431 and it would largely be dealt with without the Emperors' involvement. With all this going on several threads which Charles had held slipped permanently from his fingers; and in 1421 the Aragonese king Peter IV finally entered Naples conquering the kingdom and undermining 120 years of Hungarian policy.

Charles would die in July 1426 having failed to quell the Hussites, defeat France or make any headway with reform of the Empire. He would be succeeded by his eldest sons Sigismund and Matthew in turn.